询问湿位涡剖面图问题

YU011045

'reinit'
'sdfopen F:\grads\huatu\2021.nc'
'set mpdset q_cnworld'
'set display color white'
'run 52colors.gs'
'set csmooth on'
'set grid off'
'set grads off'
'set xlpos -20'                                                                           
'set ylpos -20'

'set z 2 16'
'set zlog on'
'set time 00Z08nov2021'
*假相当位温
'define tc=t-273.15'
'define rh=r'
'define prs=lev'  
'define es=(6.112*exp((17.67*tc)/(tc+243.5)))'
'define qs=0.62197*es/(prs-0.378*es)'
'define q=rh*qs/100'
'define e=prs*q/(0.62197+q)+1e-10'
'define tlcl=55.0+2840.0/(3.5*log(tc+273.16)-log(e)-4.805)'
'define theta=(tc+273.16)*pow((1000/prs),(0.2854*(1.0-0.28*q)))'
'define eqt=theta*exp(((3376./tlcl)-2.54)*q*(1.0+0.81*q))'
*湿位涡
'define f=2*7.292*sin(lat*3.14159/180.0)*(1e-5)'
'define g=9.8'
'define dp=100*(lev(z-1)-lev(z+1))'
'define deqt=eqt(z-1)-eqt(z+1)'
'define du=u(z-1)-u(z+1)'
'define dv=v(z-1)-v(z+1)'
'define dx=2.0*6370949.0*cos(lat*3.14159/180.0)*3.14159/180.0'
'define dy=2.0*6370949.0*3.14159/180.0'
'define dtx=cdiff(eqt,x)'
'define dty=cdiff(eqt,y)'
'define pv1=-g*(vo+f)*deqt/dp'  
'define pv2=g*((dv/dp)*(dtx/dx)-(du/dp)*(dty/dy))'
'define pv=pv1+pv2'
'set gxout shaded'
'set cint 0.2'
'set cthick 7'
'set lev 1000 400'
'set lon 110 135'
'set lat 42'
'set clevs -100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100'
'set ccols 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61'
'd pv1*10e6'
'run cbar_matlab.gs 5 1 0'
'set gxout contour'
'set ccolor 1'
'set black 0 0'
'd pv2*10e6'
'set font 1'
'run axis.gs -type l -position o -lsize 0.2 -hoffset -0.1 -start 1000 -end 400 -interval -50'
'run axis.gs -type b  -position o -lsize 0.2 -start 110 -end 135 -interval 5 -suffix `3.'
'printim F:\grads\huatu\mpv_lon.png white x1280 y1024'

'c'
画湿位涡的时候550hpa以上没有图，是什么原因